GP14 Technical - Hull Development

Jack Holt designed the GP14, originally sponsored by the Yachting World magazine, in 1949 for home construction from the then comparatively new material of Marine Plywood. It was conceived as a General Purpose dinghy, and although equipped with wooden mast and boom, and cotton jib and mainsail, it was also excellent to row, and had a standard conversion for fitting a small outboard motor.

Since its initial launch there have been many changes to the boat but the outer hull shape and deck have remained basically unaltered.

Significant changes are as follows:

Wooden Series 1

Built to Jack Holt’s original design. Some have a full buoyancy tank under the fore deck and/or a full buoyancy tank under the rear deck. The mast sat on top of the hog and had a square heel plug.

Weight reduction – 1983

Modifications were approved to bring older boats down to weight by replacing original centreboard by one of 6mm ply and the transom by 5mm ply and reducing beam and seat slats.

Mast Step Conversion – 1991

Problems arose with heavy loading concentrated on a short length of hog. A tenon heel, which sits in a track mounted on top of a spline and pad, could replace the square heel.

Series 1 / Series 2 Conversion – 1994

A complicated task in which the centreboard case is replaced and a new raised floor is fitted and sealed to provide under floor buoyancy. Few of these conversions have been carried out.

Wooden Series 11

In 1989 two prototypes, 13098 and 13099 were produced in an attempt to modernise the interior whilst reducing cost of production. The design was approved and whilst outward appearance is changed little buoyancy bags and floorboards are dispensed with.

Mark 1 GRP Hulls

The first boat was produced in 1967 and had sail number 7002. Bourne Plastics produced the original ones with white hull and light blue decks. Four buoyancy tanks, one under the fore and aft decks and one under each sidebench. Over 400 were build but difficulties following a capsize led to a change of class rules to allow scuppers to be cut through the transom. Some were completed with wooden decks, similar in specification to those on the Series 1 Wooden Hull and became knows as Composite Boats.

Mark 11 GRP Hulls

The first boat was produced in 1969 with sail number 7930. Similar to the Mark1 GRP but the rear deck tank was removed, side tanks enlarged and the bilge keel became part of the GRP moulding. Both Thames Marine built about 260 boats numbered between 8012 and 9314, Bourne Plastics built about 1600 hulls and McComb Boats of Northern Ireland built about 50 numbered between 10682 and 11325.

Mark 111 GRP Hulls

The first boat was produced in 1977 with sail number 11487. A further refinement of the basic design with many being fitted with a glass-fibre mast step and a king post to give more support to the deck around the mast slot. There were a variety of colours for the deck but no moulding was provided for the sheet horse at the transom. Bourne plastics built about 70 until 1978 when the moulds were passed to McNulty Boats who produced a further 50 hulls with numbers between 11695 and 12515. About 80 Mark 111 boats were built by Spectrum Boats with sail numbers between 11802 and 12152.

Fibredon Mark IV FRP

The first boat was produced in 1983 with a sail number of 12516. Buoyancy was the same as the Mark III boats but a radical departure from previous practice came with the inclusion of foam, as well as glass, reinforcing. All wood, with the exception of floorboards, was dispensed with. Deck and hull were bonded with rollover fibreglass rubbing bead and the keelband, except alongside the centreboard slot, becoming part of the moulding. Available in a wide choice of colours they proved popular and about 200 were produced up to sail number 13105.

Amos FRP Boats

The first GP14 design where buoyancy was provided by tanks enclosing the space under the floorboards. The square mast step was retained with a deep recess around the step between the bow tank and the underfloor buoyancy. About 35 boats were produced by Amos up to sail number 13045 and 3 were later produced b Storrar & Relph from the moulds.

Fibredon Mark IVa FRP

Boats first produced in 1992 with sail number 13120. They responded to the SeriesII wooden hull by adding a new tray to their successful hull and deck designs, producing a boat with full underfloor buoyancy and Series II mast track. It retained the original higher centreboard case and by July 1996 some 132 boats had been delivered.

Holt Speed FRP & GRP

Boats first produced in 1996 the prototype with sail number 13489 and first production with sail number 13477.  A rational redesign produced a boat with an interior layout to rival the modern race developed dinghies.  Richard Estaugh showed the competitive nature of the boat and it soon became a best seller.  To August 1998 71 had been delivered.